Retinitis pigmentosa (RP), the most common form of rod-cone dystrophy, is caused by greater than 3100 mutations in more than 71 genes, many of which are preferentially expressed in rod photoreceptors. Cone death generally follows rod loss regardless of the underlying pathogenic mutation. Preventing the secondary loss of cone photoreceptors would preserve central visual acuity and substantially improve patients’ quality of life. In this issue of the JCI, Wang et al. demonstrate that adeno-associated virus–mediated overexpression of TGF-β1 promoted cone survival and function in 3 distinct RP models with rod-specific mutations. TGF-β1 induces microglia to metabolically tune from a glycolytic phenotype (M1) to an oxidative phenotype (M2), which associates with neuroprotection and the antiinflammatory ecosystem. Consolidating the results of this study with our current understanding of how TGF-β1 regulates microglia polarization, we highlight cell-specific metabolome reprogramming as a promising non–gene-specific therapeutic avenue for inherited retinal degenerations.
Salvatore Caruso, Joseph Ryu, Peter M.J. Quinn, Stephen H. Tsang